The distinctive taste of shiitake mushrooms comes from old logs
Oita prefecture has a long association with shiitake cultivation stretching back to the early Edo period in the 17th century. Shiitake mushrooms are still cultivated today on withered stumps of Japanese chestnut oak.
The traditional method of growing shiitake bacteria is called natural log cultivation, and involves implanting the shiitake bacterium in weathered stumps of Japanese chestnut oak. The stumps, known as hodagi, are kept in a dedicated section of forest called the hodaba. Of course, natural log cultivation is subject to the vagaries of the weather among other things, and production volumes can vary considerably. But when the conditions are right, the result is a thick, tasty and aromatic shiitake mushroom.
One of the attractions of natural log cultivation is the subtle variations in texture and flavor between the harvest seasons. Shiitake that are picked in spring, called haruko, spend longer absorbing nutrients from the log and consequently have a more powerful aroma and stronger flavor. Shiitake harvested in autumn (akiko), meanwhile, benefit from the warmer temperatures and tend to be larger, with a softer bite.
The land mass of Oita prefecture varies considerably in altitude, from one meter above sea level near the coast to more than 700 meters up in the mountains. This produces a wide range of micro-climates that suit different sub-species of shiitake.According to Mr. Watanabe from the Oita Prefecture Shiitake Growers’ Association (OSK for short), Oita produces about 35 different sub-species of shiitake, more than anywhere else in Japan. We are standing in a marketplace that is filled with the heady aroma of fresh picked shiitake that have been trucked in from various parts of the prefecture.
“Nearly all of the shiitake we deal with at OSK is naturally cultivated in chestnut oak logs,” explains Watanabe. “The shiitake you see here at the marketplace are kept in cold storage to preserve the quality and keep them fresh.”
In addition to the sub-species, shiitake are often categorized in terms of other criteria such as the spread of the crown, as denoted by terms such as donko and koshin. The degree of spread can come down to a matter of few hours in terms of the time of harvest. For example, donko are harvested while the crown is closed over and tend to be thicker than koshin, which are harvested with the crown open. Donko shiitake, notable for the striking tortoiseshell pattern, are highly sought after. At the time of our visit, the beautiful-looking hana-donko variety is fetching good prices. With winter approaching, it won’t be long before the white-skinned donko, featuring a design of intricate cracks on the crown, begins to make an appearance.
Timing is critical
Shiitake farmers are called nabashi in Oita. As part of our investigations we pay a visit to Kusuo Ono, known locally as meijin (“the master”), an award-winning nabashi and recipient of a number of prizes including the coveted Ministry of Agriculture, Forestry and Fisheries Prize. We are going to visit Ono’s hodaba, which is up in the mountains at an altitude of over 500 meters. As we arrive, the sound of cattle lowing can be heard. Ono runs livestock in addition to his shiitake operations. The cattle help to maintain a good supply of cultivation logs by wandering through the forest eating up the grass, thereby promoting the growth of chestnut oak trees.
As we walk into the mountains we spy a number of hodaba. Soon we reach the one that belongs to Ono, where we see row upon row of neatly arranged hodagi stumps. It must require a great deal of patience and effort to maintain them all and carefully pick each shiitake mushroom from its home when it comes to harvest time.
Ono is constantly working on his hodaba. Particularly during the spring and autumn harvest seasons, he has to keep a close eye on the weather conditions. Natural log cultivation is highly susceptible to variations in ambient temperature and humidity. The shape and quality of the shiitake can be affected by just a single overnight drop in temperature or unexpected rainfall.
“Stimulating the hodagi helps to activate the bacteria,” explains Ono as he deftly manipulates the stumps, “and this in turn helps to promote mushroom growth. So we do things like tap them with a hammer, or occasionally invert the stumps.”
During the harvest season, timing is critical; just a few hours can be the difference between a good result and a bad result. Ono inspects the shiitake at least three times per day?morning, noon and evening?and sometimes even comes down in the middle of the night armed with a flashlight.
Ono also has his own special drying technique. While most growers dry their shiitake mushrooms in a dryer to prevent discoloration, Ono prefers a combination of machine drying and natural sunlight. “Too much time in the sun certainly alters the surface color and then buyers won’t pay as much for them,” he explains. “But I’m of the belief that a bit of sun really brings out the flavor. As long as you watch them carefully while they’re in the sun, you can get the best of both worlds.”
Producing quality shiitake mushrooms is both time-consuming and time-critical, particularly with respect to the harvesting and drying processes. It seems that the concept of seasonality for the shiitake mushroom is literally a question of hours.
Watching Ono at work, you realize how shiitake farming requires endless patience and the human touch, a process that does not lend itself to mechanization. Ono’s dedication and expertise is symbolic of the quintessential essence of Japanese manufacturing.
Oita prefecture, the spiritual home of shiitake cooking
Our research takes us to two very different establishments to sample some dishes prepared with natural log cultivated shiitake mushrooms.
The first one is called Sato no Eki?Yasuragi Kosaten, and it is located just a few minutes from Ono’s hodaba. This is a direct sales cooperative that was set up in 2003 to help local farmers find new markets for their produce.
It includes a cafeteria where you can try a variety of dishes made with natural log cultivated shiitake mushrooms. We try the excellent Genboku Donko sushi, featuring generous pieces of donko shiitake wrapped in a large sushi roll. It has a refreshing taste and benefits from the unmistakable aroma and texture of fresh shiitake.Next we head to Yufuin, a well-known hot spring resort located roughly in the middle of Oita prefecture, to find a restaurant called Kamenoi Bessou Yunotake-Ann.
Next we head to Yufuin, a well-known hot spring resort located roughly in the middle of Oita prefecture, to find a restaurant called Kamenoi Bessou Yunotake-Ann.
The elegant streetscapes of Yufuin are a major draw card for domestic and foreign tourists alike, and the town is bustling with visitors. Kamenoi Bessou Yunotake-Ann is a quaint little restaurant with its very own hodaba garden where you can view the shiitake growing in their logs. Here you can enjoy a delightfully simple dish known as Aburi Shiitake, which consists of generously proportioned shiitake toasted gently over a charcoal stove and seasoned only with salt. This is surely the best way to enjoy the true natural flavor and aroma of shiitake.
Oita prefecture offers a wide variety of places to try shiitake mushrooms, from the humble surrounds of the cafeteria in Sato no Eki Yasuragi Kosaten to the elegant fine dining experience at Kamenoi Bessou Yunotake-Ann.
Oita is a popular tourist destination, famed for its numerous hot spring resorts. But it’s more than just hot springs. So next time you visit, be sure to enjoy some of the delicious local shiitake. You won’t be disappointed!